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Geothermal Energy is a very attractive source of naturally-occurring green renewable energy. Exploiting this natural resource is straightforward and causes almost no ill effects to the environment. But, while geothermal does not suffer the intermittence of other renewable sources, its extraction efficiency is fairly modest as compared to other sources. As a result, there has been significant interest recently in hybrid systems that integrate geothermal and other forms of energy to increase the output efficiency. This work will survey the different possible integrations involving geothermal energy. A review of the literature shows that the most common hybrid systems implementation involve the integration of geothermal with solar (45% of systems) followed by the integration of a cooling tower into the geothermal system (30% of systems). This work will also investigate the applications for geothermal hybrids and show that 44% of systems are designed for heating applications. Another 44% are used for cooling while only 12% are designed for electrical power generation. Complexity of control remains as the main obstacle facing hybrid multi-source energy systems including those involving geothermal energy. Image 1 • Hybrid geothermal systems (HGS) have low initial and operating costs. • HGSs can supply all types of energy demands and decrease the effect of peak loads. • HGSs reduce negative environmental impact of energy systems. [ABSTRACT FROM AUTHOR]

• Three designs of photovoltaic-based skylights are proposed to save energy in buildings. • The integration of vacuum glazing with photovoltaic skylights is evaluated. • Using a vacuum layer at the backside of the PV layer is favorable for thermal insulation. • Using a vacuum-based PV skylight reduces the total U-value from 6.3 to 1.9 W/m2.K at ASTM. • Using the vacuum layer with the PV-skylight slightly decreases the power generation of the PV. In commercial buildings with large glazing facades, transparent facades and skylights play a considerable impact on energy consumption. In this study, three different photovoltaic (PV) -based skylights are compared to save energy in these buildings. The first skylight uses a vacuum glazing sample as a substrate at the backside of the PV layers. The second design integrates a vacuum glazing layer in front of the PV layers. And lastly, the PV layers are attached to a single layer of glazing with a solar cells covers 25% of the whole area. A 3D thermal model is developed and validated with data from the literature to compare these designs. it is concluded that using a vacuum layer at the backside of the PV layer is favorable for thermal insulation and attains relatively similar power generation to the case without a vacuum layer. In more detail, replacing the single glazing PV skylight with the first skylight design reduces the total U-value of the glazing from 6.3 to 1.9 W/m2.K for a glazing sample with an area of 0.4 m by 0.4 m at ASTM boundary conditions. Furthermore, at received solar irradiance of 1000 W/m2, an ambient temperature of 25 °C, and a wind speed of 1 m/s, replacing the third skylight design with the first skylight design slightly reduced the electricity generation from 37.4 W/m2 to 36.4 W/m2, significantly decreased the heat flux transfer from 91.1 W/m2 to 50.5 W/m2 and lowers the indoor surface temperature from 32.1 °C to 27.1 °C. [ABSTRACT FROM AUTHOR]

Historically, technological advancements in rechargeable batteries have been accomplished through discoveries followed by development cycles and eventually through commercialisation. These scientific improvements have mainly been combination of unanticipated discoveries and experimental trial and error activities. However, with the increased complexity of rechargeable battery systems and diversification in ever-demanding new applications requires a strategical approaches to commercialise newly developed battery chemistries. This can only be achieved by fast-tracking the transfer of key finding from scientific laboratories to industrial collaborators in order to design commercially feasible devices. Despite the dominance of lithium-ion batteries (LiBs) commercially in current rechargeable battery market which ranges from small scale applications such as portable electronic devices to large scale applications including transportation to grid scale electrical energy storage. Scientific community is endeavouring to consolidate the global rechargeable battery portfolio with the alternative rechargeable battery systems based on cost-effective, safe, and environmentally friendly battery chemistries. This brief prospective will provide an update on the historical developments, current technological scenario and future expectations, current and potential applications, and challenges faced by current and future rechargeable battery technology. • Brief overview working principle of different rechargeable battery systems. • Technological progression of rechargeable battery technology. • Challenges face by current battery technology. • Current and emerging applications of rechargeable batteries. [ABSTRACT FROM AUTHOR]

• NiCo-CNC@C nanoarchitectures are successfully prepared. • NiCo-CNC@C electrode is highly advantageous for supercapacitors. • NiCo-CNC@C electrode displays a specific capacity of 194.8 mAh/g at 1 A/g. • HSCs cell demonstrates specific energy of 72.6 Wh kg−1 at specific power of 1780 W kg−1. The family of transition metal carbides (TMCs) has been rapidly expanded since the discovery of the Ti 3 C 2 MXenes for various energy-orientated applications. The metal-like electronic conductivity of TMCs is suitable for getting the high-power capability for the energy storage system. However, the practical applications of TMCs are still overwhelming owing to their poor redox activity and limited energy-storing capacity. Herein, a highly conductive yet redox-active metallic nickel–cobalt intertwined cobalt–nickel carbide@carbon (NiCo-CNC@C) nanoarchitecture cathode was developed for the high-performance hybrid supercapacitor. Experimental analysis reveals that the incorporation of metals in metal carbide enhances the electronic states, minimizes the barriers in reaction kinetics, and improves redox-active species, thus boosting electrochemical performance. Accordingly, the obtained NiCo-CNC@C-700 with optimized material composition presents a high specific capacity of 194.8 mAh/g at 1 A/g with exceptional rate capability (76.8 % at 20 A/g). Moreover, a hybrid solid-state supercapacitor assembled with NiCo-CNC@C-700 and WO 3 @C as positive and negative electrodes delivers a specific energy density of 72.6 Wh kg−1 at specific power of 1780 W kg−1 and superior cycle stability. The proposed approach of metals blended with metal carbides proves their feasibility by regulating the redox reactivity of materials to encompass their practices in upcoming energy storage applications. [ABSTRACT FROM AUTHOR]

Supercapacitors are considered comparatively new generation of electrochemical energy storage devices where their operating principle and charge storage mechanism is more closely associated with those of rechargeable batteries than electrostatic capacitors. These devices can be used as devices of choice for future electrical energy storage needs due to their outstanding performance characteristics. Based on their performance, supercapacitors can be placed somewhat in middle of rechargeable batteries and conventional electrostatic capacitors since supercapacitors have higher energy and power densities when compared with electrostatic capacitors and rechargeable batteries respectively. Supercapacitors have seen increased use recently as stand-alone as well as complementary devices along with other energy storage systems such as electrochemical batteries. Therefore, it is believed that supercapacitors can be a potential alternative electrochemical energy storage technology to that of widely commercialised rechargeable batteries especially lithium-ion batteries. In this brief prospective, authors have attempted to present an overview of the evolution of supercapacitor technology and its current/future applications. • Technological evolution of supercapacitors has been covered. • Supercapacitor has been evaluated as an energy storage device. • Classification of supercapacitors has been discussed. [ABSTRACT FROM AUTHOR]

This special issue is dedicated to the research presented and discussed at the 8th International Conference on Sustainable Energy & Environmental Protection held from the 11th to the 14th August 2015 in Paisley, Scotland. The contents of this special issue are within the aims and scope of Renewable and Sustainable Energy Reviews. The aim of the International conferences on Sustainable Energy & Environmental Protection is to gather experts, practitioners and early career researchers together in a relaxed environment to present their research findings. The articles published in this special issue summarise a snapshot of the diverse range of topics from bioenergy and biogas, energy storage and district heating and energy in buildings to carbon emissions, carbon flux in soil and social aspects of carbon discussed at the conference within the framework of sustainable development. A total of eighteen extended manuscripts were invited by for consideration for publication following the conference and after a robust review process by experts in the field a total of ten articles were accepted. [ABSTRACT FROM AUTHOR]

The growing energy demands has led to a soaring level of greenhouse gas (GHG) production, with the implementation of EU legislations, the production of GHG and waste is being curbed but with an economic disadvantage. Multiple industries face losing their competitive edge due to the restrictions currently in place due to the inability to readily burn fossil fuels. With developments of thermal and physical waste management, multiple companies are utilising waste heat technologies to recapture previously lost energy to be used in other applications. The spectrum of papers in this special issue can be split into two main themes recovering energy to be used in other applications such as waste heat recovery applications and thermoacoustic engines and energy conversion via pyrolysis. Such technologies featured in the special edition reflect the growing need for a solution to reduce the production of greenhouse gases but also lower the level of global warming. [ABSTRACT FROM AUTHOR]

Quantum dots are semiconductor nanoparticles containing a range of materials with a core-shell structure. They receive discernible attention in today's world due to their potential applications, from energy storage devices to medical applications. Nevertheless, there are many approaches to their synthesis and stability routes. This review focuses on two approaches for the synthesis of quantum dots, namely surface functionalization and quantum dot doping. In addition, their stability routes were discussed, such as the intermediate shell approach, alloyed core/shell approach, shell thickness approach, ligand design approach, and over-coating approach. The review concludes by addressing the recent progress of quantum dots applications, notably in photocatalysis for different applications, such as cathode, anode, and membranes for fuel cell applications, solar cells, sensors, and various energy storage devices applications. • QDs are characterized by their tunable size, composition, and fluorescence features. • Functionalization and doping of QDs are the main remarkable achievements in synthesis. • The stability of QDs can be enhanced by following the core-shell structure. • QDs can be stabilized by the intermediate shell approach, alloyed core/shell approach, and overcoating approach. [ABSTRACT FROM AUTHOR]

With the growing demand for green technologies, hydrogen energy devices, such as Proton Exchange Membrane (PEM) fuel cells and water electrolysers, have received accelerated developments. However, the materials and manufacturing cost of these technologies are still relatively expensive which impedes their widespread commercialization. Additive Manufacturing (AM), commonly termed 3D Printing (3DP), with its advanced capabilities, could be a potential pathway to solve the fabrication challenges of PEM parts. Herein, in this paper, the research studies on the novel AM fabrication methods of PEM components are thoroughly reviewed and analysed. The key performance properties, such as corrosion and hydrogen embrittlement resistance, of the additively manufactured materials in the PEM working environment are discussed to emphasise their reliability for the PEM systems. Additionally, the major challenges and required future developments of AM technologies to unlock their full potential for PEM fabrication are identified. This paper provides insights from the latest research developments on the significance of advanced manufacturing technologies in developing sustainable energy systems to address the global energy challenges and climate change effects. • The AM technologies relevant to PEM fabrication are reviewed. • Corrosion performance of AM materials in the PEM working environment is presented. • The challenges and prospects of AM for PEM fabrication are discussed. • AM has the potential to revolutionize the fabrication of PEM systems. [ABSTRACT FROM AUTHOR]

In this study we investigated the potential use of coffee waste feedstock in biodiesel production, considering economic viability, technical feasibility, and environmental compatibility. The investment potential for a small-scale biodiesel production facility (8000 t/y) was gauged by estimating relevant economic performance indicators. Biodiesel was then extracted from spent coffee grounds and blended with fossil diesel to develop four blends: B5, B10, B15, and B20. The conformity of this fuel with relevant standards (ASTM D6751 and ISO EN14214) was determined by characterizing and adjusting the fuel's properties during the production process. The technical and environmental performance of these blends was then tested in a single-cylinder compression ignition engine with an extended range of engine speeds under three engine loading conditions (100%, 75%, and 50%), using pure diesel fuel for benchmark comparisons. The evaluated economic metrics paint an optimistic picture of investment in this project. Waste coffee could result in improved economic performance over other feedstocks. Diesel fuel outperformed the biodiesel blends in terms of engine power, thermal efficiency, and fuel economy, whereas the blends were superior in terms of exhaust gas temperature; average exhaust gas temperature drops of 11 °C and 35.2 °C were measured under full load conditions for B5 and B20, respectively. All blends emitted lower levels of CO 2 , CO, and HC than did diesel, but higher NOx emissions were present, all proportional to the blend used. Our results clearly show that SCG has great potential as a feedstock for biodiesel production, given its derivation from existing waste materials, cleaner but comparable performance, and economically viable production. • Spent coffee grounds (SCG) are a potential feedstock for biodiesel production. • SCG are an existing waste product requiring no further cultivation for fuel production. • Economic analysis of an 8000 t/y plant indicated potential for financial viability. • Technical analysis showed that SCG biodiesel performs comparably to regular diesel. • Tailpipe emissions of CO, CO 2 , and HC were lower (NOx was higher) for SCG biodiesel. [ABSTRACT FROM AUTHOR]

Thin-walled structures are frequently used as energy absorbers in the automotive, railway and aviation industries. This paper addresses the crashworthiness performance of thin-walled windowed tubes under dynamic impact loading. Different shapes of cut-outs were introduced to thin-walled tubes with different cross-sectional shapes to create windowed tubes. Explicit finite element code, LS-DYNA, was used to simulate the crushing behaviour of the windowed tubes under axial impact loading. The Finite Element (FE) model was validated by conducting experimental tests and showing that the numerical and experimental responses are comparable. The crashworthiness responses of the different windowed tubes were compared and the best performing tube was identified using a multi-criteria decision-making method known as Technique of Order Preference by Similarity to Ideal Solution (TOPSIS). It was found that a circular tube with a square window shape outperforms all other sections and exhibits the best energy absorption characteristics. Subsequently, a multi-objective optimisation analysis was performed to find the optimal configuration of the best tube. Response Surface Methodology (RSM) was used to develop models for the energy absorption responses of the tube. The design variables were selected to describe size, number, and distributions of the windows, while specific energy absorption (SEA) and peak crush force (PCF) were set as design responses. Parametric analysis was conducted to understand the effects of the design variables on the crashworthiness behaviour and the optimal configuration was identified. • The axial crushing behaviour of different simple and windowed tubes was investigated. • Crashworthiness performances of the different tubes were compared and the best tube was identified. • Response surface method and desirability approach were used to optimise the best performing tube. [ABSTRACT FROM AUTHOR]

This paper models two strategic decisions made by industrial entities: the intention to adopt a renewable energy system (RES) and the timeframe for this adoption. The methodology presented considers multiple layers of "unobserved heterogeneity." The results of random parameters imply that the parameters exhibit unobserved heterogeneity across industrial entities. For example, high non-electric energy costs increase the probability of selecting a shorter timeframe in 81.8% of entities and reduce that probability in 18.2% of entities. The results of this study also show that the majority (60%) of responding entities intend to adopt an RES within a short timeframe, generally one to two years, while 40% intend to adopt an RES three or more years after 2022. According to our findings, green bank loans, electricity tariffs, the type of industry, government bureaucracy, and entities' export capabilities predominantly influence their intention to adopt an RES. The results also show that energy-intensiveness (e.g., industrial entities in the plastic and rubber, food and drinks, and chemicals and paints sectors), high electricity tariffs, and elevated non-electric energy costs often expedite the adoption process (resulting in shorter adoption timeframes). Government impediments tend to cause entities to delay their adoption decisions. Capital costs are by far the largest impediment to adoption, as indicated by 29.3% of the surveyed entities, followed by government legislation at 18.6%. The findings presented offer crucial knowledge for creating opportunities to implement new policies and produce an environment in which industries can expedite their transitions to renewable energy. • Solar PV demand by the industrial sector is addressed through heterogeneity models. • Two key decisions are addressed: the intention to adopt and the adoption timeframe. • Heterogeneity in means and variances of the random parameters are accounted for. • Several explanatory variables turned out to influence the two demand decisions. • Heterogeneity models are statistically superior to fixed parameters models. [ABSTRACT FROM AUTHOR]

Over the past several decades, a noticeable amount of research efforts has been directed to minimising injuries and death to people inside a structure that is subjected to an impact loading. Thin-walled (TW) tubular components have been widely employed in energy absorbing structures to alleviate the detrimental effects of an impact loading during a collision event and thus enhance the crashworthiness performance of a structure. Comprehensive knowledge of the material properties and the structural behaviour of various TW components under various loading conditions is essential for designing an effective energy absorbing system. In this paper, based on a broad survey of the literature, a comprehensive overview of the recent developments in the area of crashworthiness performance of TW tubes is given with a special focus on the topics that emerged in the last ten years such as crashworthiness optimisation design and energy absorbing responses of unconventional TW components including multi-cells tubes, functionally graded thickness tubes and functionally graded foam filled tubes. Due to the huge number of studies that analysed and assessed the energy absorption behaviour of various TW components, this paper presents only a review of the crashworthiness behaviour of the components that can be used in vehicles structures including hollow and foam-filled TW tubes under lateral, axial, oblique and bending loading. [ABSTRACT FROM AUTHOR]

The world is moving towards renewable energies as an alternative to fossil fuels. The photovoltaic technologies have the highest capacity increase rate among all the renewable energy systems throughout the last decade. Therefore, the huge amounts of photovoltaic wastes from such significant global installations are inevitable and needs to be dealt with sooner than later to increase the potential of PVs being an affordable and clean energy source. This work is split into two parts with different models. The first one mathematically models the PV waste projection using the Weibull distribution and socio-environmental decision-making factors while connecting them to the power purchase agreements (PPAs). This model uses data from both c-Si and CdTe PV projects in the United Arab Emirates (UAE). This model's results showed the possibility of increasing the PV projects operational age in UAE to 30 years for both technologies with 2030 being the best and latest year to start PV waste management procedures with the profitable reusability of PVs after projects' decommissioning. The second part is an optimization model for the PV waste and installations management by controlling the total future PV installations and possible PV replacements, while considering budget limitations and dismantling capacities. With a planning horizon until the year of 2100, this model's results suggest annually installing 670 MW of new PVs to achieve 50% of the country's consumption by 2030 and 100% by 2040 without any power shortage or outage. Finally, the models are flexible and extremely beneficial for future works for improvements, results comparison, and to design PV waste management centers or dismantling facilities. • Projected PV wastes through socio-environmental factors and Weibull distribution. • Built an optimization model to balance PV installations with waste replacements. • Unprecedently improved both c-Si and CdTe PV waste management plans in the UAE. • Install 670 MW of PVs annually to achieve 50% of the country's consumption by 2030. • Required annual replacements will start exceeding 100 MW by 2040. [ABSTRACT FROM AUTHOR]

An experimental and numerical investigation on the thermal and mechanical response of a lined pipe (compound pipe) under welding is presented. The welding process consists of a single-pass overlay welding (inner lap-weld) and a two-pass girth welding (outer butt-weld). The influence of the filler material of the girth welding has been examined thermally and mechanically as it is a key factor that can affect the quality of lined pipe welding. To this end, a three-dimensional non-linear finite element model based on the ABAQUS code has been developed and successfully validated against small-scale experimental results. This study was conducted on two specimens of lined pipe joined together by a girth welding deposited either by mild steel or by austenitic stainless steel. Furthermore, in this study, a pre-heat treatment required to produce lined pipe specimens has been taken into account. Strains and residual stresses have been measured by means of high temperature strain gauges, residual stress gauges and the X-ray diffraction technique along the inner and outer surfaces of the welded lined pipe whereas the thermal history has been recorded by thermocouples. The findings point out that replacing the girth welding mild steel by austenitic stainless steel has a significant effect on the residual stress results but no influence on the thermal history results. Two identical welded lined pipes connected by single-pass weld overlay and two-pass girth welding, dimensions in mm. [Display omitted] • The temperature fields are not affected by changing the girth welding material. • Replacing the girth welding to austenitic stainless steel shorten the length of residual plastic strain on the outer surface. • Beyond the fusion zones, the residual stresses are not influenced by changing the girth welding material. [ABSTRACT FROM AUTHOR]

Massive expansions in the global population and the global digitalization throughout the industrial revolution are causing energy security issues that are no longer environmentally affordable through conventional power generation systems. As an alternative solution, the global power capacities and production of the renewable energy systems in general and the photovoltaic technologies in particular, are significantly increasing every year. With a lifetime range of 25–40 years, the PV power plants will eventually and over their lifetime or cumulatively turn into large masses of waste. This work briefly reviews the market state of the three generations of PV and summarizes their most recent technical challenges. It is highlighted that the c-Si (Crystalline Silicon) and CdTe (Cadmium Telluride) technologies have a relatively high level of market maturity, least number of technical challenges, and most interesting space for sustainable development. Furthermore, a one-of-a-kind sustainable and circular PV industry's business model was developed, to directly and indirectly address the practical business and engineering gaps concerning environmental, economic, social, and technical factors affecting the circular transition of the PV industry. The model assisted in reviewing and discussing articles concerning material compositions, manufacturing processes, and dismantling processes. Previous reviews and surveys reported the lack of dedicated PV dismantling facilities and miscommunications between the supply chain stages and logistics. Therefore, a critical review was done on the most recent and comprehensive articles related to the optimizations and improvements of the PV industry's sustainability towards the anticipated circular economy. Additionally, this work highlights the objectives, key constraints, and major strategies of the sustainability's environmental, economic, and social pillars within the photovoltaic industry and business stages, which introduced the possible contributions of the industry 4.0 technologies. Therefore, a brief section was dedicated to the possible utilizations of Industry 4.0 throughout the critical stages of the photovoltaics' economy. Finally, a research road map was developed to assist all levels of future researches in optimizing the PV's circular economy and the overall sustainability of the industry. [Display omitted] • Market states, potentials, and challenges of the three generations of PV were discussed. • Crystalline silicon- and CdTe- based technologies are the dominating source of PV wastes. • A circular business model was developed for the PV industry. • Recent improvements and optimizations towards sustainable PV lifecycle were critically discussed. • A novel research roadmap is created to assist in future research on PV's circular economy. [ABSTRACT FROM AUTHOR]

In recent years, many researchers have been conducted on batteries' health monitoring and prognostics, mainly focusing on the batteries' state of charge (SOC). Accurately estimating the state of health (SOH) and predicting the remaining useful life (RUL) of battery components are very important for the prognosis and health management of the overall battery system. However, due to the non-linear dynamics caused by the electrochemical characteristics in batteries, the accurate estimations of SOC, SOH and RUL prediction are still challenging and many technologies have been developed to solve this challenge. This paper reviews and discusses state of the art in SOC and SOH and RUL estimation techniques for all battery types. A novel framework is developed and presented to compare all battery techniques based on three dimensions: battery performance (Z dimension), approaches (X dimension), and criteria (Y dimension) to fulfil. All studies are reviewed and discussed based on the dimensions and the criteria defined in the framework. Based on this investigation, this study summarizes at the end the key outcomes and suggests future research challenges. Novel framework for battery monitoring and prognostics optimization techniques comparison. [Display omitted] • Batteries' health monitoring and prognosis. • Predicting the battery service life. • Techniques for battery health monitoring and management. • Framework to compare all battery techniques based on the performance and the criteria to fulfil. [ABSTRACT FROM AUTHOR]

Energy storage materials have been receiving attention during the past two decades. Supercapacitors, in specific, have emerged as promising energy storage devices, especially for flexible electronics. The development of supercapacitor materials is crucial to advance their performance and multifunctionality. Supercapacitors have been shown to possess higher energy densities than conventional capacitors and higher power densities than batteries. Advancements in electrochemical supercapacitor cells are heavily sought after. This review showed that the progress made in supercapacitors' materials led to the development of novel electrode materials, heat-resistant separators, flexible supercapacitors, and highly conductive electrolytic solutions. Therefore, supercapacitors' electrochemical performance, power density, charge storage density, specific capacitance, and charge/discharge rates were eventually enhanced. Moreover, research is being conducted to operate supercapacitors in soft electronics by improving their solid-state flexibility. This paper also provided a comprehensive overview of the recent developments in high-temperature capacitive energy storage, the various applications of supercapacitor cells in the industry, supercapacitors design, as well as the challenges involved. This work concluded that the biggest challenge of producing supercapacitors is manufacturing them at a low cost to make them economically viable energy storage options. [Display omitted] • A review of the recent developments of materials design for supercapacitors is presented. • Machine learning and 3D printing appear to be promising for flexible supercapacitors. • Novel electrolyte materials include ionic liquids and anhydrous gel electrolytes. • The challenges include the safety, the cost, and the durability of electrolyte materials. [ABSTRACT FROM AUTHOR]

Ammonia as an energy storage medium is a promising set of technologies for peak shaving due to its carbon-free nature and mature mass production and distribution technologies. In this paper, ammonia energy storage (AES) systems are reviewed and compared with several other energy storage techniques. It is shown that once optimized for commercial use, AES systems have the potential for cost-effectiveness and efficiency. Its independence of topographic or climatic resource availability makes it an ideal option for many locales that has no provisions for pumped-hydro storage or with too harsh a climate for electrochemical batteries to survive. The range of applications for AES systems covers common utility-scale storage and includes electric vehicles applications. In this review, the viability of ammonia as a hydrogen carrier is discussed in detail, especially as a thermochemical energy storage media, and as a fuel for fuel cells and internal combustion engines. The health and safety impacts of ammonia are also highlighted and discussed. • Ammonia offers an attractive energy storage system due to its well-established infrastructure. • Ammonia showed great promise as a viable hydrogen fuel carrier. • Energy can be stored in the chemical bonds of ammonia through the endothermic ammonia synthesis reaction. • Ammonia can be used as a fuel in fuel cells and internal combustion engines. • The challenges as well as future research directions ammonia storage systems are highlighted. [ABSTRACT FROM AUTHOR]

Recent studies have reported improved biogas and methane yield from marine biomass when the particle size is mechanically reduced and the specific surface area available to enzymes is increased prior to anaerobic incubation. Although the advantage of reducing the particle size has been identified, an ideal particle size that would offer greater yield with a positive energy balance has not been identified for such substrate to date. As particle size reduction by mechanical means is often highly demanding in energy, this paper attempts to fill this gap for macroalgal biomass by identifying the particle size distribution allowing the highest biogas and methane yields obtained in a previous work. The study estimated that when about 80% of the particles are sized below 1.6 mm 2 , a biogas and methane yield improvement of up to 52% and 53% respectively can be achieved. The results are discussed in relation to the biogas yield, related methane content and potential inhibitory phenomena occurred during the fermentation. [ABSTRACT FROM AUTHOR]

This work details the construction and testing of a biological photovoltaic cell (BPV) that utilizes solar energy to generate electricity from biological photosynthetic activities of microorganisms. Nannochloropsis Oculata , a marine microalgae that can survive in hot climates with good photosynthetic activity is used and the potential of energy conversion is investigated and compared to microalgae species native to the UAE salt flats. The species are added with a copper mesh that acts as a photoanode material to increase the reactive surface area and produce an economical and ecofriendly BPV. The chronoamperometry and I–V tests were done first as a proof-of-concept to ensure the electrochemical activity and electricity generation from the cell. A pulse-modulated fluorescence monitoring system was used to analyze photosynthetic metrics which is the overall photosynthetic efficiency from Chlorophyll fluorescence. The Nannochloropsis cell has the potential to intrinsically capture carbon dioxide during photosynthesis which is estimated to have an efficiency of 89.1 % in the closed system. This will result in a more sustainable approach to produce energy while reducing CO2 emissions. [ABSTRACT FROM AUTHOR]

This study investigates the impact of ground albedo, module spacing, height, and tilt angle on the annual energy output of a small-scale residential photovoltaic (PV) system. The study used response surface methodology (RSM) integrated with PVsyst simulation tool for the analysis. The results obtained from PVsyst are verified by comparing them with data from existing literature. Two significant contributions were demonstrated in this study: a parametric analysis that evaluates the influence of several parameters on the annual energy output, and a detailed statistical analysis that utilizes RSM with optimization. The central composite design with 30 runs was used for the experimental design. Within the tested ranges, the findings indicate that ground albedo, module spacing, and module tilt angle significantly affect annual energy generation. The RSM generated a statistical model that predicts the system's annual energy generation, with a determination coefficient (R2) of 0.99. Moreover, the RSM can identify the optimal values of the studied controllable parameters, which can lead to improved system performance and increased energy output. The optimization analysis reveals that the system's highest annual energy output is attained when the ground albedo is set at 0.82, the module spacing is 8.95 m, the module height is 1.35 m, and the module tilt angle is 35.7°. These parameters were determined based on the weather conditions in Sharjah, UAE. The findings reveal that the annual energy production of the tilted bifacial PV (T-BiPV's) improves by 12.4 %, when ground albedo is increased from 0.2 to 0.8. Also, the output increases by 69.47 % when spacing is increased from 2 m to 8 m. Additionally, increasing the height of the T-BiPV modules from 0.5 m to 2 m results in an increase in energy output by 5.63 %. This study can serve as a basis for further investigations into optimizing bifacial PV systems using RSM, particularly under restricted module spacing or when taking land cost into account in the optimization. [ABSTRACT FROM AUTHOR]

This study investigates the impact of ground albedo, module spacing, height, and tilt angle on the annual energy output of a small-scale residential photovoltaic (PV) system. The study used response surface methodology (RSM) integrated with PVsyst simulation tool for the analysis. The results obtained from PVsyst are verified by comparing them with data from existing literature. Two significant contributions were demonstrated in this study: a parametric analysis that evaluates the influence of several parameters on the annual energy output, and a detailed statistical analysis that utilizes RSM with optimization. The central composite design with 30 runs was used for the experimental design. Within the tested ranges, the findings indicate that ground albedo, module spacing, and module tilt angle significantly affect annual energy generation. The RSM generated a statistical model that predicts the system's annual energy generation, with a determination coefficient (R2) of 0.99. Moreover, the RSM can identify the optimal values of the studied controllable parameters, which can lead to improved system performance and increased energy output. The optimization analysis reveals that the system's highest annual energy output is attained when the ground albedo is set at 0.82, the module spacing is 8.95 m, the module height is 1.35 m, and the module tilt angle is 35.7°. These parameters were determined based on the weather conditions in Sharjah, UAE. The findings reveal that the annual energy production of the tilted bifacial PV (T-BiPV's) improves by 12.4 %, when ground albedo is increased from 0.2 to 0.8. Also, the output increases by 69.47 % when spacing is increased from 2 m to 8 m. Additionally, increasing the height of the T-BiPV modules from 0.5 m to 2 m results in an increase in energy output by 5.63 %. This study can serve as a basis for further investigations into optimizing bifacial PV systems using RSM, particularly under restricted module spacing or when taking land cost into account in the optimization. [ABSTRACT FROM AUTHOR]

Abstract: Compared to laparoscopic surgery for interval tubal sterilization, the transcervical approach is an effective method of female sterilization which obviates the requirement of general anesthesia and surgical incision. However, current methods of transcervical sterilization are unable to provide an instant occlusion. This paper focuses on the design, development and testing of a novel implant (James E., Coleman, Christy Cummins, 2009. Anastomosis Devices and Method. US Patent 20090105733A1) to achieve instant permanent female sterilization via the transcervical approach. The implant is designed to be deployed under hysteroscopic visualization into the ostium of the fallopian tube and relies on instant mechanical occlusion. The implant includes two sets of wings that penetrate into the ostium and uterine muscle tissue and trap the tissue in between thus plugging the entrance of the fallopian tube. In order to design the shape of implant wings and to investigate the mechanical behavior of the implant, a three-dimensional (3D) model was developed and Finite Element Method (FEM) was used for simulations. The implant was validated by a number of successful deployments in bench testing, animal tissue and explanted human uteri. During the deployments in animal tissue and explanted uteri, it was observed that the two sets of wings completely trapped the tissue in between and the hydraulic pressure testing of the explanted uteri using saline solution and methylene blue proved the instant occlusion of the fallopian tubes. Initial results suggest that this novel implant provides a safe and effective method of female sterilization. Further development work is ongoing in preparation for “first-in-man” clinical trials. [Copyright &y& Elsevier]

• Improved performance and longer service life would help the adoption of PEM electrolyzers for large-scale hydrogen production. • The Digital Twin could use real-time information from the system's sensors to optimise control and system life. • The data-driven approach improves knowledge of the plant's operating conditions by explicating latent information. Operating electrolyzers for producing green hydrogen is a critical emerging issue because of either the broader use of hydrogen for several scopes or the short life span and efficiency of these components. Digital Twin offers a new opportunity to effectively face these problems by improving online control and providing fault detection, diagnosis, and prediction services. Since the Digital Twin is, in fact, a virtual mirror of a real system continuously updated by information received from the field, it allows it to swiftly react to small signals of departure from standard or optimal conditions. Although Digital Twins are widely applied in different fields, comprehensive guidance on developing and designing a Digital Twin in the literature is still lacking. This manuscript aims to provide a comprehensive guide on how to build the Digital Twin of a PEM-Electrolyzer. In particular, the architecture of the Digital Twin is initially presented, then all its components are analyzed, showing the steps to be performed to build a Digital Twin for operating PEM-Electrolyser system. [ABSTRACT FROM AUTHOR]

Hydrogen has been gaining tremendous attention as a promising energy carrier that has the potential to replace other conventional fuels, which correspondingly leads to a magnificent reduction in greenhouse emissions and tackles other environmentally related aspects. Despite the number of practical technologies being implemented for producing hydrogen, research has been specifically concentrating on developing renewable energy-driven approaches for green hydrogen generation, such as solar, wind, biomass, and geothermal routes. This study summaries the recent advancements in photovoltaic-based hydrogen production systems. Electrolysis driven by various photovoltaic (PV) technologies, and its subsystems' barriers were also displayed. Moreover, those systems' overall hydrogen generation effectiveness has been reported by evaluating their STH "solar-to-hydrogen" conversion efficiency. Furthermore, it was found that the major barriers related to the technologies under investigation are related to safety, production, storage, exploitation, commercialization, weather conditions' variations, and PV cell cooling. [ABSTRACT FROM AUTHOR]

• Mechanical energy storage systems are very efficient in overcoming the intermittent aspect of renewable sources. • Flywheel, pumped hydro and compressed air are investigated as mechanical energy storage. • Parameters that affect the coupling of mechanical storage systems with solar and wind energies are studied. Mechanical energy storage systems are among the most efficient and sustainable energy storage systems. There are three main types of mechanical energy storage systems; flywheel, pumped hydro and compressed air. This paper discusses the recent advances of mechanical energy storage systems coupled with wind and solar energies in terms of their utilization. It also discusses the advances and evolution in each type and compares them in terms of performance, capacity, response and utilizations. The reviewed studies exhibit all parameters that affect the performance of each storage type in which the configuration of the system has the major effective role. Choosing the suitable mechanical storage type depends on the requirements of each application such as using the flywheel for short duration applications. If long duration is needed, then it is preferred to use either pumped hydro or compressed air storage systems, knowing that the former has higher efficiency while the latter provides a faster start up. For the sake of the environment, it is recommended to use the adiabatic or isothermal compressed air storage. In all cases that combine MESSs with solar or wind energy, the series connection is preferred in order to provide stability and better control strategy. [ABSTRACT FROM AUTHOR]

This article presents a novel method to improve energy absorption performance of thin-walled circular tubes under quasi-static lateral loading through the preforming process. Desirable investigations are carried out by experimental tests and numerical simulations. Firstly, simple circular tubes are shaped into four different types (P1–P4) of preformed specimens, using a semi–cylindrical Teflon die and various blade-shaped indenters with semi–cylindrical nose. Then, the preformed specimens are laterally compressed between two rigid platens to perform flattening tests and their mechanical behaviors are investigated during the lateral flattening experiments, based on viewpoint of energy absorption. Some experiments are carried out and due to the test limitations, numerical simulations are performed, using the ABAQUS/Explicit software. In the following, based on the finite element analysis, various preformed specimens with different geometrical characteristics are simulated to investigate influences of wall thickness, preformed type and internal spanof the specimen cross–section and also, effects of loading direction on energy absorption performance of the preformed specimens. Also, some simple circular tubes are flattened as the benchmark and results of four types of the preformed samples are compared with the corresponding benchmark. The obtained results illustrate that by shaping the simple circular tubes into the preformed specimen, a new hollow prismatic samples are produced that their energy absorption capability is 11.5 times of the corresponding value of the benchmark; consequently, the present article suggest the preformed specimens of various types instead of the corresponding simple circular tubes, as better energy absorber. • This article suggests a new method to enhance absorbed energy by thin-walled tubes. • Circular tubes are shaped into preformed samples by a Teflon die and indenters. • Four types of preformed specimens are produced and used in the flattening process. • A simple circular tube is laterally compressed as the benchmark. • Results of the preformed specimens are compared with the benchmark results. [ABSTRACT FROM AUTHOR]

Abstract The world energy consumption is greatly influenced by the aviation industry with a total energy consumption ranging between 2.5% and 5%. Currently, liquid fossil fuel, which releases various types of Greenhouse Gas (GHG) emissions, is the main fuel in the aviation industry. As the aviation industry grows rapidly to meet the requirements of the increased world population, the demand for environmentally friendly power technology for various applications in the aviation sector has been increased sharply in recent years. Among the various clean power sources, energy obtained from hydrogen is considered the future for energy generation in the aviation industry due to its cleanness and abundance. This paper aims to give an overview of the potential aviation applications where hydrogen and fuel cell technology can be used. Also, the major challenges that limit the wide adoption of hydrogen technology in aviation are highlighted and future research prospects are identified. Highlights • The use of hydrogen as a propulsion fuel in the aviation industry is reviewed. • Hydrogen production and storage technologies are explored. • The various aerospace and aviation applications of fuel cell technology are identified. • The major challenges that limit the wide adoption of hydrogen technology in the aviation sector are discussed. [ABSTRACT FROM AUTHOR]

Abstract In this work, a tri-reforming process was coupled with a membrane separation unit to enhance efficiency of ammonia (NH 3) synthesis process in terms of CO 2 emission, NH 3 production, and NO x emission. Primary and secondary reformers were replaced by a tri-reforming process, while a Perovskite membrane was applied to separate nitrogen (N 2) from oxygen (O 2). A conventional NH 3 synthesis process and the proposed process were simulated by Aspen-Hysys and compared in order to investigate the performance of the proposed sterategy. The simulation results indicated that when temperature increased and pressure decreased, conversion of hydrocarbons and H 2 /CO ratio were improved from 1.73 to 2.54, which resulted in an increase in NH 3 production by 27 %, and a decrease in CO 2 emission rate from 1192 kg/h to approximately 1 kg/h. The proposed sterategy was optimized in terms of different parameters e.g., temperature and pressure. Optimum reaction pressure and temperature were determined to be between 1 and 10 bar and 500–800 °C, respectively. The results of the study revealed that the proposed strategy not only removed amine and methanol sweeteners which reduce the operational costs of the process, but also decreased the NO x content from 8220 ppm to almost 10 ppm. Graphical abstract Unlabelled Image Highlights • A tri-reforming process was coupled with a membrane separation unit to enhance the ammonia synthesis process efficiency. • Increasing temperature and decreasing pressure improved the hydrocarbons conversion and H 2 /CO ratio. • The proposed strategy increased NH 3 production and reduced CO 2 emission simultaneously. [ABSTRACT FROM AUTHOR]

Abstract The greenhouse gases emissions produced by industry and power plants are the cause of climate change. An effective approach for limiting the impact of such emissions is adopting modern Carbon Capture and Storage (CCS) technology that can capture more than 90% of carbon dioxide (CO 2) generated from power plants. This paper presents an evaluation of state-of-the-art technologies used in the capturing CO 2. The main capturing strategies including post-combustion, pre-combustion, and oxy – combustion are reviewed and compared. Various challenges associated with storing and transporting the CO 2 from one location to the other are also presented. Furthermore, recent advancements of CCS technology are discussed to highlight the latest progress made by the research community in developing affordable carbon capture and storage systems. Finally, the future prospects and sustainability aspects of CCS technology as well as policies developed by different countries concerning such technology are presented. Graphical abstract Unlabelled Image Highlights • The main carbon capture technologies are reviewed. • Comparison between the types of carbon capture technology is presented. • Challenges of using these technologies in the capture of carbon dioxide is discussed. • Future prospects of some of these technologies is presented. [ABSTRACT FROM AUTHOR]

Abstract Carbon capture and storage (CCS) is now known to be an effective way to reduce greenhouse gas emissions especially CO 2 to the atmosphere. Amino acid salt (AAS) solutions are regarded as promising CO 2 absorbents compared to traditional amine solutions, as they are environmentally being with lower evaporation as well as fewer degradation issues. This paper is intended to review recent developments in CO 2 capture using AASs. The thermodynamics and kinetics of CO 2 and different AASs are illustrated in detail. We will also discuss the blended solutions containing AASs in terms of applications and absorption or regeneration performance. Additionally, we will present specific directions for future research on CO 2 -AAS systems. This paper could provide a guideline for effective carbon capture by new absorbents. Highlights • A comprehensive review of amino acid salts fundamentals is introduced. • Detailed thermodynamics and kinetics between CO 2 and various amino acid salts are discussed. • The developments of CO 2 capture by amino acid salts in the fields of biogas upgrading, natural gas and flue gas purification are illustrated. [ABSTRACT FROM AUTHOR]

Sustainability targets can be achieved by pursuing environmental-friendly and energy-efficient design and construction. Being sub-standard in terms of stability, buildings would pose serious threats to the environment and natural sources. Therefore, having sustainable design and construction is of great importance in building industry. To achieve sustainability targets, recently recycled aggregates attracted special attention. While several studies have been conducted on the thermal and hydrometric characteristics of recycled materials, there are few studies available on the evaluation of the applicability of these materials in buildings. Accordingly, in this study, the performance of four different recycled concrete panels, produced using waste and recycled materials, has been investigated in terms of energy consumption in a residential building using Design-Builder software. Moreover, a model tree algorithm (M5′) has been used to evolve formulas for predicting the total energy consumption in the reference building. To do this, up to 1200 simulations using various recycled materials and glass areas have been carried out in Design-Builder software. The performances of the developed formulas have been evaluated on the basis of statistical measures. The results suggest that M5′ could serve as a valuable tool for the estimation of total energy consumption in residential buildings. [ABSTRACT FROM AUTHOR]

To reduce the carbon dioxide foot print, it is unescapable to adopt an energy policy that incorporates simultaneously renewable energy systems as well as smart energy strategies such as heat recovery. In the frame of this view, a heat recovery approach is suggested. The heat is recovered from drain water. It is then utilized to enhance the performance of heat pump within two schemes. Directly by replacing the ambient air heating the evaporator and indirectly by preheating the air heated by the condenser. The suggested approach is a numerical and experimental method that, on one hand, relies on experiments to determine the temperature of the drain water and on the other hand, it uses an iterative procedure to solve the energy balance equation and the mass balance equation. To that end an in-house code is developed. It allows to evaluate the heat efficiency of the heat recovery system as well as the performance of the heat pump. It has been shown that using such system may enhance the Coefficient of Performance up to 400%. In addition, economic and environmental studies are performed to assess the economic and environmental impact of the proposed techniques. [ABSTRACT FROM AUTHOR]

This paper reviews the common existing designs of flow plates of fuel cells and suggests modifications to some of them to help reduce the pressure drop in the flow channels. Pressure drop is one of the factors that influence the overall performance of the cell both directly and indirectly through interaction with other factors including water management in the cell. The work uses computational fluid dynamics (CFD) to examine different design and study the effect of varying the flow rate (i.e. velocity) on the pressure drop for each of the designs modelled. Again, the designs are optimized by changing different parameters using ANSYS CFX. Results showing the effects of the modifications on pressure drop in the various plates are presented in this paper. From the study of the various designs, a conclusion was drawn that a modification of fuel cell designs in existence using a system similar to the diesel injection system design approach reduced the pressure drop in the fuel cell as shown by the simulation results. This reduction in pressure drop will contribute to the improvement of performance but it must be stressed that other factors also contribute to the overall performance of the cell and reduction in pressure drop alone is not a guarantee of better performance of a certain fuel cell design. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are a promising solution for energy storage in various applications, such as electric vehicles and building facilities. However, they are immensely sensitive to the working temperature, requiring good thermal management. Here various thermal management technologies are reviewed considering both high and low working temperatures and thus cooling and heating systems. In all, 18 cooling and 64 heating techniques are thorougly described and critically compared in terms of complexity, efficiency, heating or cooling rate, scope of applicability, and the types and sizes of batteries to which they apply. The conclusions provide a solid background for further investigations, and recommendations for future work are suggested. [ABSTRACT FROM AUTHOR]

• An integrated adsorption-absorption system for cooling and desalination was developed. • The absorption cycle showed exergy efficiency lower than the adsorption cycle. • Transient heat sources impose a degree of irreversibility, causing various cyclic heat. • Marginal differences were between the internal combustion engine's waste and steady heat. The scarcity of clean water and the lack of sustainable cooling systems are continuously pressing. Although many technologies are well-established, such as vapour compression for refrigeration and reverse osmosis for desalination, they are energy-intensive and conventional refrigeration technology utilising working fluids of long-lasting ozone-depleting and greenhouse effects. Alternatively, adsorption and absorption technologies can meet such demands, and they are the most feasible to utilise the waste and renewable heat abundant in many locations. Therefore, this paper computationally studies the emerging integrated adsorption-absorption system for cooling cum desalination employing transient waste heat sources of various waveform characteristics. A previously validated computational model for the adsorption subsystem was coupled with a thermodynamic model for the absorption subsystem and experimental heat profiles obtained from an internal combustion engine. The energy and exergy analysis of the integrated system utilising the actual heat source from an internal combustion engine and predefined waveforms were undertaken and benchmarked against that operated under steady heat sources. The integrated system operated with a relatively low exergy efficiency in the absorption cycle of up to 15.33%. The adsorption bottoming cycle successfully utilised the heat from the absorption subsystem at a relatively higher exergy efficiency of up to 42.69%. The execution of a transient heat source of sinusoidal waveform enhanced the water production by up to 30% and the cooling of absorption and adsorption subsystems by 24% and 15%, respectively. However, admitting realistic waveforms of an internal combustion engine showed marginal differences compared to the steady heat sources owing to their high frequencies and small amplitudes. [ABSTRACT FROM AUTHOR]

• A hybrid photovoltaic system with water storage and desiccant is evaluated for poly-generation. • The hybrid system outperforms both rooftop PV and BIPV/T systems alone. • Over 50% more electricity is generated, with at least 60% lower heating and cooling loads. • Inflation has a particularly strong influence on the payback time. • High sensitivity of storage tanks volume to the thermal comfort setpoint is seen. There is a growing effort towards the application of solar technologies to meet electrical and thermal demand. However, substantial energy is used in buildings around the world for electricity and thermal comfort. Here we evaluate a novel hybrid solar-powered system for reducing the load on the direct expansion and heat pump unit of a combined heating and air conditioning system while generating electricity. The system combines rooftop photovoltaic (PV) and building-integrated photovoltaic thermal (BIPV/T) systems for electricity generation, while any excess electricity is used to drive a hot and cold water storage system. A residential building in Tehran is used as a case study, and the results are computed via MATLAB, TRNSYS, and Carrier HAP software. The system is shown to outperform both rooftop PV and BIPV/T systems alone, generating at least 50% more electricity while reducing the heating and cooling loads on the machinery by at least 60%. The system also enjoys a payback time of 2.87 years. The impact of thermal comfort setpoints, in addition to inflation and discount rates, are also evaluated via a sensitivity analysis involving several key performance metrics, namely the hot and cold water storage volumes, the size of the desiccant wheel, and the payback time. The cooling load is found to have the greatest influence on the cold water storage volume and the desiccant size, with 80.1% and 41.2% variations for baseline variations of ±20%. With a 57.7% increase, the heating load is found to have the biggest influence on the hot water storage volume. With a 27.1% variation, inflation has the strongest effect on the payback time. [ABSTRACT FROM AUTHOR]

• Metal chalcogenides can perform selective catalysis for ORR, and low poisoning catalysis for fuel oxidation. • 3 electrodes system examines catalysts' activity for ORR or fuel oxidation, and in-situ tests mimic the cell's real time operation. • Various synthesis routes can tailor metal chalcogenides to fit desirable dimensions, sizes, stoichiometries, and morphologies. The shift in the energy sector toward green resources makes fuel cells increasingly relevant as a supplier of green and sustainable energy. However, factors such as expensive catalysts, anodic poisoning, and fuel crossover reduce the lifetime and performance of the fuel cells, necessitating catalysis improvement. This review article presents the unique capabilities of metal chalcogenides (MC) as tailored catalysts, elucidating their synthesis, testing techniques, and performance evaluations. MC catalysts are matured via various physical and chemical methods to control their morphology, quantity, dimension, and size. Upon synthesis, the catalyst performance is quantified using three-electrode cells, followed by tests in fuel-cell prototypes. As anodic catalysts, MCs oxidize various fuels such as methanol, ethanol, urea, and impure H 2 at high current densities and low onset potentials, while hindering the poisoning species. As cathodic catalysts, MCs exhibit current values similar to that exhibited by their noble metal counterparts while reducing oxygen selectively in the vicinity of the fuels via four electron transfers at a wide range of potentials. [Display omitted] [ABSTRACT FROM AUTHOR]

Fuel cells are among the promising sources of clean energy, considering the low costs, low acoustical pollution, and the high-energy conversion. The remarkable features of graphene and its derivatives have triggered research studies on their applications in PEMFCs. PEMFCs still face some operational challenges for large-scale applications, including high costs, low proton conductivities at high temperatures, mechanical/thermal stabilities, and high fuel crossover. The unique characteristics of graphene-based materials, i.e., high electrochemical stability, good mechanical strength, large surface area, and excellent thermal stability, have been exploited in PEMFCs. This review discusses the potential role of graphene and graphene oxide (GO) in the membranes' structural modifications, and utilization of polymer matrices such as SPEEK, PBI, PANI, SPAES, Nafion, and PVA polymers. The synthesis/functionalization of GO has been investigated with novel composite membranes and mechanisms involved in the enhancements of proton conductions, water uptakes, IECs, and power densities. Graphene materials showed excellent dispersion in solvents and alteration of membrane morphologies. The preceding properties are attributed to the formation of oxygen-based functional groups in GO nano-layers. The incorporation of graphene in other fuel cells, i.e., direct methanol fuel cells and biofuel cells, has exhibited commendable performance and appeared promising for commercial applications, especially with the reduction of fuel crossover. [Display omitted] • Graphene oxide materials in proton exchange membranes are discussed. • Graphene oxide incorporation is achieved due to its compatibility with many solvents. • Graphene oxide modification showed enhanced electrochemical properties in proton exchange membranes. • Reduced fuel crossover was reported in proton exchange graphene oxide-based membranes. [ABSTRACT FROM AUTHOR]

Membrane cost, long-term stability, and sustainability are major concerns when selecting membranes in microbial fuel cells (MFCs) for scaling-up applications. In recent years, efforts have been made to improve reactor architectural designs and to explore ceramic membrane materials, aiming to achieve techno-economical sustainability and efficiency. Furthermore, ceramics have recently emerged as low-cost separators, electrodes, and chassis materials for MFC applications. The introduction of cation exchange minerals into ceramic membranes promotes high proton transfer with improved membrane characteristics. High cationic transfer, proton exchange rate, stability against thermochemical conditions, structural strength to withstand high hydraulic load, and long-term stability with easy biofouling mitigation support the utilization of such membranes for scaling-up use. Successful field trials of Pee-power MFC, stacked urinal MFC, bioelectric toilet, and others showed the feasibility of ceramic membranes for practical applications. Therefore, this review emphasized the membrane characteristics, substantial effect of mineral additives, scaling-up applications, recent developments, and perspectives toward the practical utilization of MFC-based ceramic membranes. [Display omitted] • Ceramic membranes as low-cost alternatives to polymeric membranes in fuel cells. • Ceramics have a wide scope as membranes, electrodes, and chassis for fuel cells. • Long-term stability, high cation exchange rate make ceramics suitable for upscaling. • Cation mineral addition in membranes promotes proton transfer & membrane properties. • Successful scalable trials are positive indicators for fuel cell commercialization. [ABSTRACT FROM AUTHOR]

• Investigation of shallow geothermal energy in Bekaa-Lebanon is performed. • Ground temperature measurement at different depths is carried out. • Comparison between direct and indirect ground cooling systems is presented. The aim of this paper is to investigate the potential of using shallow geothermal energy in Lebanon for cooling a power cycle. The study includes ground temperature measurement, operating system management, and pressure drop assessment. Temperatures were monitored at six positions underground reaching to a depth of 2 m in Bekaa-Lebanon during the whole of 2020. The temperature sensors were placed at depths of 0.3, 0.6, 1, 1.3, 1.6, and 2 m underground. At 2 m depth, the ground temperature showed high stability with an annual temperature difference of 7 °C, while that of high and low ambient temperatures were 40 °C and 33 °C, respectively. Based on the comparison between ambient and ground temperatures, the ground cooling system can operate 207 days/year partially with full operations of 51 days. This shows that shallow geothermal energy has a great potential to activate a ground-based cooling system in this region. However, to avoid heat accumulation, use of another heat exchanger is recommended to support the ground cooling system. This heat exchanger can also provide coolth compensation when the power cycle is turned off. The pressure drop inside the heat exchangers was found to be highly significant, hence, it was essential to add an intermediate water loop between the power cycle and the ground loop. [ABSTRACT FROM AUTHOR]

• Ni-Co 4 N nanoparticles laminated on nitrogen-doped (NC) carbon are successfully prepared. • Ni-Co 4 N@NC is extremely beneficial for supercapacitor. • Ni-Co 4 N@NC electrode displays specific capacity of 397.5 mA h g−1 at 1 A g−1. • HSCs cell demonstrates specific energy of 57.2 Wh kg−1 at a specific power of 843.8 W kg−1. The self-supported integrated structure of electrode consisting of heteroatoms is advantageous for high-performance energy storage applications. Herein, we developed heteroatomic Ni-Co 4 N nanoparticles laminated on highly conductive nitrogen-doped carbon (NC) matrix through in-situ nitridation for high energy and stable hybrid supercapacitor (HSC). The plenty of rendering electrochemically active sites, specifically, single-atom Ni, Co 4 N nanoparticles, and heteroatomic N-doped carbon matrix, and their several synergistic effects facilitate fast electron transfer and superior electrochemical performance. Benefiting from these merits, the resultant Ni-Co 4 N@NC electrode demonstrates robust electrochemical activity with high specific capacity of 397.5 mA h g−1, high rate capability of 72.4% and superior cycling stability over 10,000 cycles. The heteroatomic Ni-Co 4 N@NC electrode is further employed for the HSC cell beside with the activated carbon (AC) electrode, which establish the specific energy of 57.2 Wh kg−1 at a specific power of 843.8 W kg−1 and cyclic stability of 89.7% after 15,000 cycles. The present study highlights the utilization of heteroatomic self-supported metal nitrides for the high energy HSCs cell, paving the way to the expansion of highly efficient electrode materials for the future energy storage systems. [ABSTRACT FROM AUTHOR]

It is now well established that electrochemical systems can optimally perform only within a narrow range of temperature. Exposure to temperatures outside this range adversely affects the performance and lifetime of these systems. As a result, thermal management is an essential consideration during the design and operation of electrochemical equipment and, can heavily influence the success of electrochemical energy technologies. Recently, significant attempts have been placed on the maturity of cooling technologies for electrochemical devices. Nonetheless, the existing reviews on the subject have been primarily focused on battery cooling. Conversely, heat transfer in other electrochemical systems commonly used for energy conversion and storage has not been subjected to critical reviews. To address this issue, the current study gives an overview of the progress and challenges on the thermal management of different electrochemical energy devices including fuel cells, electrolysers and supercapacitors. The physicochemical mechanisms of heat generation in these electrochemical devices are discussed in-depth. Physics of the heat transfer techniques, currently employed for temperature control, are then exposed and some directions for future studies are provided. [ABSTRACT FROM AUTHOR]

With the rapid evolution of photovoltaic systems and technologies, many challenges arise in their installation and operation. Since both developed and developing countries have a significant proliferation of solar PV systems both on grid and off grid, suitable technological solutions must be proposed to mitigate such challenges. In this review paper, recent advances in all different generations of available solar PV technologies cell are discussed, with the main emphasis on solar panel temperature control via various cooling technologies. Furthermore, a matching of PV panels and corresponding cooling method is presented, with a focus on PV/T systems. Life cycle assessment analysis (LCAA) for PV and PV/T systems including environment and economy is also discussed. Future recommendations are made to facilitate and evaluation of the most challenges faced the PV cooling technologies. [Display omitted] • The three generations of technologies of solar cells were reviewed and discussed. • Different types of cooling systems based on the air, water, and advanced were reviewed. • Life cycle analysis assessment of PV system on the environment and economic was studied. [ABSTRACT FROM AUTHOR]